/*
* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
- * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#include <linux/hdreg.h>
#include <linux/blktrace_api.h>
+#define DM_MSG_PREFIX "core"
+
static const char *_name = DM_NAME;
static unsigned int major = 0;
static unsigned int _major = 0;
+static DEFINE_SPINLOCK(_minor_lock);
/*
* One of these is allocated per bio.
*/
union map_info *dm_get_mapinfo(struct bio *bio)
{
- if (bio && bio->bi_private)
- return &((struct target_io *)bio->bi_private)->info;
- return NULL;
+ if (bio && bio->bi_private)
+ return &((struct target_io *)bio->bi_private)->info;
+ return NULL;
}
+#define MINOR_ALLOCED ((void *)-1)
+
/*
* Bits for the md->flags field.
*/
#define DMF_BLOCK_IO 0
#define DMF_SUSPENDED 1
#define DMF_FROZEN 2
+#define DMF_FREEING 3
+#define DMF_DELETING 4
struct mapped_device {
struct rw_semaphore io_lock;
struct semaphore suspend_lock;
rwlock_t map_lock;
atomic_t holders;
+ atomic_t open_count;
unsigned long flags;
bioset_free(dm_set);
if (unregister_blkdev(_major, _name) < 0)
- DMERR("devfs_unregister_blkdev failed");
+ DMERR("unregister_blkdev failed");
_major = 0;
{
struct mapped_device *md;
+ spin_lock(&_minor_lock);
+
md = inode->i_bdev->bd_disk->private_data;
+ if (!md)
+ goto out;
+
+ if (test_bit(DMF_FREEING, &md->flags) ||
+ test_bit(DMF_DELETING, &md->flags)) {
+ md = NULL;
+ goto out;
+ }
+
dm_get(md);
- return 0;
+ atomic_inc(&md->open_count);
+
+out:
+ spin_unlock(&_minor_lock);
+
+ return md ? 0 : -ENXIO;
}
static int dm_blk_close(struct inode *inode, struct file *file)
struct mapped_device *md;
md = inode->i_bdev->bd_disk->private_data;
+ atomic_dec(&md->open_count);
dm_put(md);
return 0;
}
+int dm_open_count(struct mapped_device *md)
+{
+ return atomic_read(&md->open_count);
+}
+
+/*
+ * Guarantees nothing is using the device before it's deleted.
+ */
+int dm_lock_for_deletion(struct mapped_device *md)
+{
+ int r = 0;
+
+ spin_lock(&_minor_lock);
+
+ if (dm_open_count(md))
+ r = -EBUSY;
+ else
+ set_bit(DMF_DELETING, &md->flags);
+
+ spin_unlock(&_minor_lock);
+
+ return r;
+}
+
static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
struct mapped_device *md = bdev->bd_disk->private_data;
if (r > 0) {
/* the bio has been remapped so dispatch it */
- blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
- tio->io->bio->bi_bdev->bd_dev, sector,
+ blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
+ tio->io->bio->bi_bdev->bd_dev, sector,
clone->bi_sector);
generic_make_request(clone);
/*-----------------------------------------------------------------
* An IDR is used to keep track of allocated minor numbers.
*---------------------------------------------------------------*/
-static DEFINE_MUTEX(_minor_lock);
static DEFINE_IDR(_minor_idr);
-static void free_minor(unsigned int minor)
+static void free_minor(int minor)
{
- mutex_lock(&_minor_lock);
+ spin_lock(&_minor_lock);
idr_remove(&_minor_idr, minor);
- mutex_unlock(&_minor_lock);
+ spin_unlock(&_minor_lock);
}
/*
* See if the device with a specific minor # is free.
*/
-static int specific_minor(struct mapped_device *md, unsigned int minor)
+static int specific_minor(struct mapped_device *md, int minor)
{
int r, m;
if (minor >= (1 << MINORBITS))
return -EINVAL;
- mutex_lock(&_minor_lock);
+ r = idr_pre_get(&_minor_idr, GFP_KERNEL);
+ if (!r)
+ return -ENOMEM;
+
+ spin_lock(&_minor_lock);
if (idr_find(&_minor_idr, minor)) {
r = -EBUSY;
goto out;
}
- r = idr_pre_get(&_minor_idr, GFP_KERNEL);
- if (!r) {
- r = -ENOMEM;
- goto out;
- }
-
- r = idr_get_new_above(&_minor_idr, md, minor, &m);
- if (r) {
+ r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
+ if (r)
goto out;
- }
if (m != minor) {
idr_remove(&_minor_idr, m);
}
out:
- mutex_unlock(&_minor_lock);
+ spin_unlock(&_minor_lock);
return r;
}
-static int next_free_minor(struct mapped_device *md, unsigned int *minor)
+static int next_free_minor(struct mapped_device *md, int *minor)
{
- int r;
- unsigned int m;
-
- mutex_lock(&_minor_lock);
+ int r, m;
r = idr_pre_get(&_minor_idr, GFP_KERNEL);
- if (!r) {
- r = -ENOMEM;
- goto out;
- }
+ if (!r)
+ return -ENOMEM;
+
+ spin_lock(&_minor_lock);
- r = idr_get_new(&_minor_idr, md, &m);
+ r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
if (r) {
goto out;
}
*minor = m;
out:
- mutex_unlock(&_minor_lock);
+ spin_unlock(&_minor_lock);
return r;
}
/*
* Allocate and initialise a blank device with a given minor.
*/
-static struct mapped_device *alloc_dev(unsigned int minor, int persistent)
+static struct mapped_device *alloc_dev(int minor)
{
int r;
struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
+ void *old_md;
if (!md) {
DMWARN("unable to allocate device, out of memory.");
return NULL;
}
+ if (!try_module_get(THIS_MODULE))
+ goto bad0;
+
/* get a minor number for the dev */
- r = persistent ? specific_minor(md, minor) : next_free_minor(md, &minor);
+ if (minor == DM_ANY_MINOR)
+ r = next_free_minor(md, &minor);
+ else
+ r = specific_minor(md, minor);
if (r < 0)
goto bad1;
init_MUTEX(&md->suspend_lock);
rwlock_init(&md->map_lock);
atomic_set(&md->holders, 1);
+ atomic_set(&md->open_count, 0);
atomic_set(&md->event_nr, 0);
md->queue = blk_alloc_queue(GFP_KERNEL);
if (!md->disk)
goto bad4;
+ atomic_set(&md->pending, 0);
+ init_waitqueue_head(&md->wait);
+ init_waitqueue_head(&md->eventq);
+
md->disk->major = _major;
md->disk->first_minor = minor;
md->disk->fops = &dm_blk_dops;
add_disk(md->disk);
format_dev_t(md->name, MKDEV(_major, minor));
- atomic_set(&md->pending, 0);
- init_waitqueue_head(&md->wait);
- init_waitqueue_head(&md->eventq);
+ /* Populate the mapping, nobody knows we exist yet */
+ spin_lock(&_minor_lock);
+ old_md = idr_replace(&_minor_idr, md, minor);
+ spin_unlock(&_minor_lock);
+
+ BUG_ON(old_md != MINOR_ALLOCED);
return md;
blk_cleanup_queue(md->queue);
free_minor(minor);
bad1:
+ module_put(THIS_MODULE);
+ bad0:
kfree(md);
return NULL;
}
static void free_dev(struct mapped_device *md)
{
- unsigned int minor = md->disk->first_minor;
+ int minor = md->disk->first_minor;
if (md->suspended_bdev) {
thaw_bdev(md->suspended_bdev, NULL);
mempool_destroy(md->io_pool);
del_gendisk(md->disk);
free_minor(minor);
+
+ spin_lock(&_minor_lock);
+ md->disk->private_data = NULL;
+ spin_unlock(&_minor_lock);
+
put_disk(md->disk);
blk_cleanup_queue(md->queue);
+ module_put(THIS_MODULE);
kfree(md);
}
/*
* Constructor for a new device.
*/
-static int create_aux(unsigned int minor, int persistent,
- struct mapped_device **result)
+int dm_create(int minor, struct mapped_device **result)
{
struct mapped_device *md;
- md = alloc_dev(minor, persistent);
+ md = alloc_dev(minor);
if (!md)
return -ENXIO;
return 0;
}
-int dm_create(struct mapped_device **result)
-{
- return create_aux(0, 0, result);
-}
-
-int dm_create_with_minor(unsigned int minor, struct mapped_device **result)
-{
- return create_aux(minor, 1, result);
-}
-
static struct mapped_device *dm_find_md(dev_t dev)
{
struct mapped_device *md;
if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
return NULL;
- mutex_lock(&_minor_lock);
+ spin_lock(&_minor_lock);
md = idr_find(&_minor_idr, minor);
- if (!md || (dm_disk(md)->first_minor != minor))
+ if (md && (md == MINOR_ALLOCED ||
+ (dm_disk(md)->first_minor != minor) ||
+ test_bit(DMF_FREEING, &md->flags))) {
md = NULL;
+ goto out;
+ }
- mutex_unlock(&_minor_lock);
+out:
+ spin_unlock(&_minor_lock);
return md;
}
atomic_inc(&md->holders);
}
+const char *dm_device_name(struct mapped_device *md)
+{
+ return md->name;
+}
+EXPORT_SYMBOL_GPL(dm_device_name);
+
void dm_put(struct mapped_device *md)
{
struct dm_table *map;
- if (atomic_dec_and_test(&md->holders)) {
+ BUG_ON(test_bit(DMF_FREEING, &md->flags));
+
+ if (atomic_dec_and_lock(&md->holders, &_minor_lock)) {
map = dm_get_table(md);
+ idr_replace(&_minor_idr, MINOR_ALLOCED, dm_disk(md)->first_minor);
+ set_bit(DMF_FREEING, &md->flags);
+ spin_unlock(&_minor_lock);
if (!dm_suspended(md)) {
dm_table_presuspend_targets(map);
dm_table_postsuspend_targets(map);
projects / linux-2.6-omap-h63xx.git / blobdiff